--- src/libspf2/spf_compile.c.orig	Mon Feb 20 08:26:43 2012
+++ src/libspf2/spf_compile.c	Wed Apr 19 18:53:10 2017
@@ -577,7 +577,7 @@ SPF_c_parse_macro(SPF_server_t *spf_server,
 		switch (src[idx]) {
 		case '%':
 			if (spf_server->debug > 3)
-				SPF_debugf("Adding literal %%");
+				SPF_debugf("%s", "Adding literal %");
 			SPF_ENSURE_STRING_AVAIL(1);
 			*dst++ = '%';
 			ds_len++;
@@ -586,7 +586,7 @@ SPF_c_parse_macro(SPF_server_t *spf_server,
 			
 		case '_':
 			if (spf_server->debug > 3)
-				SPF_debugf("Adding literal space");
+				SPF_debugf("%s", "Adding literal space");
 			SPF_ENSURE_STRING_AVAIL(1);
 			*dst++ = ' ';
 			ds_len++;
@@ -595,7 +595,7 @@ SPF_c_parse_macro(SPF_server_t *spf_server,
 
 		case '-':
 			if (spf_server->debug > 3)
-				SPF_debugf("Adding escaped space");
+				SPF_debugf("%s", "Adding escaped space");
 			SPF_ENSURE_STRING_AVAIL(3);
 			*dst++ = '%'; *dst++ = '2'; *dst++ = '0';
 			ds_len += 3;
@@ -604,8 +604,8 @@ SPF_c_parse_macro(SPF_server_t *spf_server,
 
 		default:
 			if (spf_server->debug > 3)
-				SPF_debugf("Adding illegal %%-follower '%c' at %d",
-				src[idx], idx);
+				SPF_debugf("Adding illegal %%-follower '%c' at %lu",
+				src[idx], (unsigned long)idx);
 			/* SPF spec says to treat it as a literal, not
 			 * SPF_E_INVALID_ESC */
 			/* FIXME   issue a warning? */